Question

What is the electric field 30cm from a charge 𝑞 = 4 × 10⁻⁹𝐶?

Answer 1

Explanations & Calculations

• Just apply Coulomb's law formula to the situation.

$\qquad\qquad \begin{aligned} \small \vec{E}&=\small k.\frac{Q}{r^2}\\ &=\small (9\times10^9\,Nm^2C^{-2}).\frac{4\times10^{-9}C}{(0.03\,m)^2}\\ &=\small 4.0\times10^4\,NC^{-1} \end{aligned}$